Is mx record means once anyone want to send the mail to others, they have to go to dns to register a one mx record , that is a domain name, such as hotmail .com, in this domain name will point to at least one address of the server.

So , it introduce reverse dns, which is , when I send the mail to the others, the other side will check whether the 'from' ip has a domain name in public dns , if the ip can not find any domain name related to it, the mail server will block the incoming message.

Is my concept correct? And what is A record and PTR do ?

closed as off topic by womble, EEAA, mailq, voretaq7 Aug 3 '12 at 16:07

Questions on Server Fault are expected to relate to server, networking, or related infrastructure administration within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here. If this question can be reworded to fit the rules in the help center, please edit the question.

  • Re: the last line of your question, And what is A record and PTR do ?, I STRONGLY suggest picking up a copy of DNS and BIND -- This question indicates a fundamental lack of understanding re: the concepts underlying DNS, which this book will help remedy. – voretaq7 Aug 3 '12 at 16:09

If I send an e-mail to yourdomain.com, it checks for the MX-records of yourdomain.com to find which mailserver(s) handles this.

Your second paragraph is correct. Many enables the option to check the reverse lookup of the IP sending the e-mail.

Your concept is correct indeed!

A-record is a record pointing to the IP-address of a server. A typical record could look like: yourdomain.com 521 IN A (<- random IP)

When you run a ping against yourdomain.com it will try the IP listed in the A-record.

PTR records are reverse lookup records.

I hope any of this makes sense!

  • To add: you are not supposed to send emails froma home server, use a real server / your provider to rlay. Home servers are notoriously ONLY sending spam. Noone accepts email from dynamic address space. – TomTom Mar 27 '12 at 8:50
  • then what is the difference of mx and a record? – foodil Mar 27 '12 at 8:53
  • MX is specific for mail-traffic. – xstnc Mar 27 '12 at 8:54
  • is mx record is for email domain and a record is for webpage? – foodil Mar 27 '12 at 8:54
  • That's one way of putting it yes! – xstnc Mar 27 '12 at 8:55

Not the answer you're looking for? Browse other questions tagged or ask your own question.